ORA-01722: invalid number while passing value from inner select query to the top select query - oracle

Question

FOR the ISBN['9780495809135'] if CATEGORY_EXISTS column return as 1234,3454 then query is throwing below error.if it returns single row then its not throwing error.
I want to write in the topmost query say if CATEGORY_EXISTS ='Category Not Found' then FILE_NAME column then should display as 'files not found' otherwise pass the CATEGORY_EXISTS values with comma separated to top most most query.
Please note that this is just pseduo query,in the actual query lot of other tables and joins are there,
ORA-01722: invalid number
01722. 00000 - "invalid number"
*Cause: The specified number was invalid.
*Action: Specify a valid number.
SELECT ISBN ,
(SELECT LISTAGG(ANP.FILE_NAME, ',') WITHIN GROUP (
ORDER BY ANP.FILE_NAME)
FROM TABLE1 T
WHERE T.NODE_ID IN( CATEGORY_EXISTS)
)FILE_NAME
FROM
(SELECT ISBN,
(SELECT (
CASE
WHEN COUNT(DISTINCT AN.ID) > 0
THEN LISTAGG(AN.ID, ',') WITHIN GROUP (
ORDER BY AN.ID)
ELSE 'Category Not Found'
END )
FROM TABLE1 aca
JOIN TABLE2 AN
ON ACA.CHILD_NODE_ID=AN.ID
WHERE PARENT_NODE_ID=GT_CHILD_NODE_ID
) CATEGORY_EXISTS
FROM
(SELECT ISBN,
(SELECT ID FROM TEMP_CHILD_ASSOC ac WHERE CHILD_NODE_NAME=GT.ISBN
) GT_CHILD_NODE_ID
FROM MAIN_TABLE GT
WHERE ISBN='9780495809135'
)
);

Answer 1

The listagg() function generates a string of comma-separated values (if there is more than one ID). The case expression gives you either that generated string, of the fixed text literal (if there are no IDs). You are then trying to compare that string to a number; effectively one of these:
WHERE T.NODE_ID IN ('4321')
WHERE T.NODE_ID IN ('1234,3454')
WHERE T.NODE_ID IN ('Category Not Found')
You are implicitly converting the string to a number to compare it with NODE_ID. The first one will work as the implicit conversion is valid. The second will give you ORA-01722 (unless you have exactly two values, and your NLS decimal separator is a comma; but still won't give a match), and the third will also give that error - because those strings cannot be converted to numbers.
It's possible you are expecting the second one to be magically treated as two numbers inside the IN() clause, but that isn't how it works; it's getting a single string literal, not an actual list of numbers it can understand.
The IN condition does accept a list of multiple comma-separated expressions, but you are passing in a single string. The fact that string happens to consist of comma-separated values is irrelevant: it is itself still just a single expression. And that cannot be converted implicitly to a number.
If you have, or can create, a schema-level table type like:
create type my_number_tab as table of number
/
then you could use the collect() function to convert the IDs into a collection instead of a string, and then use member of to find matches; something like (with a bit of interpretation of your pseudocode):
SELECT ISBN ,
(SELECT LISTAGG(ANP.FILE_NAME, ',') WITHIN GROUP (
ORDER BY ANP.FILE_NAME)
FROM TABLE3 ANP
WHERE ANP.NODE_ID MEMBER OF CATEGORIES -- use collection
)FILE_NAME
FROM
(SELECT ISBN,
(SELECT CAST(COLLECT(AN.ID) AS my_number_tab) -- create collection not string
FROM TABLE1 aca
JOIN TABLE2 AN
ON ACA.CHILD_NODE_ID=AN.ID
WHERE PARENT_NODE_ID=GT_CHILD_NODE_ID
) CATEGORIES
FROM
(SELECT ISBN,
(SELECT ID FROM TEMP_CHILD_ASSOC ac WHERE CHILD_NODE_NAME=GT.ISBN
) GT_CHILD_NODE_ID
FROM MAIN_TABLE GT
WHERE ISBN='9780495809135'
)
);
It looks like you could also join to anp inside the inner query instead, so in that you generate the string list of file names rather than (or as well as) the string list of IDs. It's hard to tell from the pseudocode though; but perhaps something like:
SELECT ISBN,
(SELECT (
CASE
WHEN COUNT(DISTINCT AN.ID) > 0
THEN LISTAGG(ANP.FILE_NAME, ',') WITHIN GROUP (
ORDER BY ANP.FILE_NAME)
ELSE 'Category Not Found'
END )
FROM TABLE1 aca
JOIN TABLE2 AN
ON ACA.CHILD_NODE_ID=AN.ID
JOIN TABLE3 ANP
ON ANP.NODE_ID=AN.ID
WHERE ACA.PARENT_NODE_ID=GT_CHILD_NODE_ID
) FILE_NAME
FROM
(SELECT ISBN,
(SELECT ID FROM TEMP_CHILD_ASSOC ac WHERE CHILD_NODE_NAME=GT.ISBN
) GT_CHILD_NODE_ID
FROM MAIN_TABLE GT
WHERE ISBN='9780495809135'
);
You could probably also do the same thing with left outer joins (though perhaps they don't all need to be), although your comment suggests you have a reason for using subqueries instead:
SELECT GT.ISBN,
CASE WHEN COUNT(AN.ID) = 0 THEN 'files not found'
ELSE LISTAGG(ANP.FILE_NAME, ',') WITHIN GROUP (ORDER BY ANP.FILE_NAME)
END AS file_name
FROM MAIN_TABLE GT
LEFT JOIN TEMP_CHILD_ASSOC ac ON CHILD_NODE_NAME=GT.ISBN
LEFT JOIN table1 aca ON aca.parent_node_id = ac.id
LEFT JOIN table2 an on an.id = ACA.CHILD_NODE_ID
LEFT JOIN table3 anp on anp.node_id = an.id
WHERE GT.ISBN = '9780495809135'
GROUP BY GT.ISBN;
or something like that; again hard to tell from the pseudocode...